The present invention relates to hydraulic systems and pertains particularly to a combined hydrostatic transmission and implement control system.
Variable displacement pumps are coming into increasingly widespread use because of their high efficiency. Fixed displacement pumps normally pump a flow of fluid continuously when in operation whereas variable displacement pumps may be arranged to pump fluid only when the fluid is needed. For this reason, the use of variable displacement pumps can result in increased efficiency, considerable savings and very low loss of energy.
One disadvantage to variable displacement pumps, however, is that they are normally somewhat more complicated than fixed displacement pumps. This complication results primarily from the need for mechanisms for varying the displacement from minimum to maximum and the provision of control means for controlling this variable displacement.
Various systems for varying the displacement of hydraulic pumps are known. Most such systems, however, are too complicated and expensive for utilization in small inexpensive hydraulic systems.